Immunology

October 2014

Clinical Challenge

Questions for this month’s clinical challenge are based on articles in this issue. The clinical challenge is endorsed by the RACGP Quality Improvement and Continuing Professional Development (QI&CPD) program and has been allocated 4 Category 2 points (Activity ID:10981).

Answers to this clinical challenge are available immediately following successful completion online at http://gplearning.racgp.org.au. Clinical challenge quizzes may be completed at any time throughout the 2014–16 triennium; therefore, the previous months answers are not published.

Case 1 – Jenny Clarke

Jenny, a biology student aged 24 years, presents to you with increasing tiredness and recurrent mouth ulcers. She has no gastrointestinal symptoms and her weight has been stable. She is otherwise healthy. Although you feel it is clinically unlikely, you would like to exclude coeliac disease and you arrange for Jenny to have some blood tests.

Question 1

Which one of the following test results excludes the diagnosis of coeliac disease?

Negative IgA-tissue transglutaminase (tTG) while on a gluten-free diet

Duodenal atrophy seen on duodenal biopsy

Negative HLA-DQ2 and HLA-DQ8

Negative IgA-tTG with low total IgA

Elevated tTG but normal DGP antibodies

Question 2

After further assessment, Jenny is found to have non-classical coeliac disease. Which one of the following dominates the clinical picture in this variant of coeliac disease?

Gastrointestinal malabsorption

Absent symptoms

Abdominal bloating

Extraintestinal symptoms

Intermittent loose bowel actions

Question 3

The pathophysiology of coeliac disease is due to the immune response being triggered by which one of the following?

Proline- and glutamine-rich proteins

Small bowel activated proteases

tTG amidates gliadin peptides

Activated T helper cells

Activated cytotoxic B helper cells

Question 4

The risk of which one of the following conditions is reduced by strict adherence to a gluten free diet?

Small bowel lymphoma

Type 2 diabetes

B-group vitamin deficiency

Obesity

Constipation

Case 2 – Jack Martin

Jack, 6 months of age, has a runny nose and rash and is brought in by his parents. You notice that Jack has not been vaccinated. His parents explain that they have chosen not to have him vaccinated as they have a number of concerns about vaccination.

Question 5

Which one of the following is the least important parental concern about vaccination that you may wish to explore with Jack’s parents?

Vaccination safety

Fear of the risk of autism due to vaccination

The presence of toxic ingredients in vaccines

Vaccines weakening the immune system

Vaccination can cause encephalitis

Jack’s parents have considered adopting a selective vaccination schedule, as they wish to avoid certain immunisations, including measles vaccine. They have a number of concerns about its safety and feel that the risk of measles is very low in Australia due to herd immunity.

Question 6

What population vaccine coverage level is required to provide optimal herd immunity for measles?

75%

80%

85%

90%

95%

Question 7

Which of the following would best describe Jack’s parents’ position on vaccination?

Unquestioning acceptor

Cautious acceptor

Hesitant

Selective vaccinator

Refuser

Question 8

Which of the following strategies might be helpful in reducing Jack’s parents’ decisional conflict regarding vaccination?

Using graphic images and narratives to explain the risks of measles

Showing them the vaccination schedule to emphasise that Jack is behind

Strongly emphasising vaccine safety

Challenging their scientific beliefs about measles vaccine

Giving them an MMR decision aid fact sheet

Case 3 – May Lim

May is 4 years of age and she presents with her mother Tammy. May experiences frequent rashes around her mouth and often complains of abdominal pains. This has occurred since she has been eating solids, from around 6 months of age. Tammy is worried that May could have a food allergy and suspects it is to soy.

Question 9

Which one of the following would confirm that May has an IgE-mediated food allergy to soy?

A positive skin prick test

Serum-specific IgE levels

Both a positive skin prick test to soy and serum-specific IgE levels related to soy

Abdominal pains and rash after eating soy and a positive skin prick test for soy

Serum-specific IgA levels

Question 10

You refer May to an allergist and she is found to have an IgE-mediated allergy to soy. What advice would you give Tammy regarding treatment for May?

She should avoid foods that contain more than 20% soy.

Baked food containing soy may accelerate her development of tolerance to uncooked soy.

Antihistamines will be of no benefit.

Her allergy to soy will be lifelong.

She needs to carry an adrenaline autoinjector.

Question 11

May also has symptoms consistent with intermittent allergic rhinitis. Which one of the following medications is not appropriate?

Second-generation antihistamines

First-generation antihistamines

Intranasal corticosteroids

Chromes

Amoxicillin

Question 12

Tammy is currently 18 weeks pregnant. She would like to know if there is anything she can do to prevent her baby developing allergies. Which one of the following has been proven to be effective?

Prebiotics during pregnancy

Probiotics to the infant from birth

Delaying the introduction of solids until 7–8months

Avoiding potentially allergenic foods until at least 12 months

Exclusively breastfeeding for the first 4–6 months

Case 4 – Zara

Rebecca is a new patient and comes to see you with her daughter Zara, aged 8 years, who has been troubled by recurrent episodes of non-specific abdominal pains for the past 12 months. Rebecca has been to several doctors and after a series of tests Zara has been diagnosed with functional gastrointestinal disorder (FGID). Rebecca has been reading around this topic on the Internet and, in her words, ‘is now more confused than ever’ about what this means. She is keen for you to explain what this problem is and advise on how best to manage Zara’s tummy pains.

Question 13

In order to be sure that you, Rebecca and Zara are all discussing the same problem, an important first step is to clearly define the problem. Which one of the following is not part of the Rome III definition of FGID?

Recurrent abdominal pain

Recurrent eczematous skin rashes on the flexures

Episodic diarrhoea

Persistent/chronic abdominal pain

Constipation

Question 14

It is important to ensure that the diagnosis of FGID is correct. Which one of the following pathology test results is consistent with this diagnosis?

Raised total IgE levels

Low serum albumin

Elevated total serum iron binding capacity

Positive anti-endomysial antibodies

Normal serum magnesium

Question 15

Food intolerance is often considered to have a significant role in symptom generation in FGID. Which one of the following dietary components is least likely to cause FGID?

Fructose

Lactose

Potassium iodide

Galactooligosaccharides

Polyols (sugar alcohols)

Question 16

Rebecca is keen to try a food elimination diet in an attempt to control Zara’s symptoms. This is an ill-advised course of action that may lead to a number of adverse outcomes. Which one of the following is the least likely adverse outcome?

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Help with downloads

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Files on the website can be opened or downloaded and saved to your computer or device.

To open click on the link, your computer or device will try and open the file using compatible software.

To save the file right click or option-click the link and choose "Save As...". Follow the prompts to chose a location.

Types of file

PDF Most of the documents on the RACGP website are in Portable Document Format (PDF). These files will have "PDF" in brackets along with the filesize of the download. To open a PDF file you will need compatible software such as Adobe Reader. If you do not have it you can download Adobe Reader free of charge.

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